CALCULATION OF WAVE RESISTANCE BY RANKINE SOURCE METHOD FOR SEVERAL TYPICAL SHIP HULLS

The three-dimensional potential flow around a ship moving at constant speed in calm water is solved by a Rankine source model. The hull and a part of the free surface are represented by panels, over which the density of the singularities is assumed to be constant. Boundary conditions are exactly satisfied on the hull and by Dawson's finite difference scheme on the free surface. Several approximations of the free-surface condition have been tested, (Neumann-Kelvin, Dawson, modified Dawson equation). The forces on the hull are computed up to the second order, which needs to take into account the trim and sinkage by a second panelisation of the hull. This method has been initially tested on simple analytical bodies, i.e. ellipsoid and thin Wigley hull. Real hulls, each with its specific problem are briefly treated: a cargo ship (Series 60), a low-speed ship (HSVA tanker), a high-speed boat with a cleared transom stern, a trawler in two versions, single-hull and twin-hull. Comparison with experimental values shows reasonably good agreement in each of these cases.